Theresa May has, for the first time, acknowledged that the British government has failed to get the public to understand its case for the use of surveillance to tackle national security threats in the wake of revelations of mass harvesting of personal data by Britain’s GCHQ and the US National Security Agency.

The home secretary admitted to defence and security experts that individual privacy and mass surveillance by the security services had become “a much more salient question for the public in the last year or so”. Under questioning, she agreed that the public lacked any real understanding of the role intelligence played in tackling threats, including organised crime.